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  • Title: Effects of methylxanthines on superprecipitation of myosin B extracted from rabbit fast skeletal muscle.
    Author: Mayahara T, Suzuki K, Ohata H, Kamimura T.
    Journal: J Biochem; 1982 Feb; 91(2):651-5. PubMed ID: 7068582.
    Abstract:
    Myosin B was extracted from rabbit fast skeletal muscle. Caffeine (2-70 mM), theophylline (2-30 mM), and theobromine (2 mM) were examined for their effects on the rate and extent of myosin B superprecipitation at a low ionic strength (50 mM KCl) and a low concentration of ATP (40 microM) by the turbidimetric method. The rate of the superprecipitation was significantly (p less than 0.05 and p less than 0.01) reduced by 30-70 mM caffeine and 2-30 mM theophylline, while the extent was significantly (p less than 0.01) increased by 10-30 mM theophylline. The onset of the superprecipitation was also delayed and a clearing phase was even induced by 50-70 mM caffeine. Theobromine had no significant effect on the rate or extent of the superprecipitation at the concentration used. These results indicate that caffeine and theophylline are retardants of the myosin B superprecipitation reaction in the concentration ranges investigated.
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